PHP - 这是在类中正确使用异常处理错误吗？

Question

我在这个主题上进行了大量搜索，并得到了很多好的（但不同的）结果。有些结果并不完全相关，最终似乎是一个偏好问题，但我感兴趣的是我是否遵循良好的设计原则。

如果这个问题太模糊，可以删除它，但你能推荐我在哪里发布吗？

此外，这只是一个示例。这里有很多事情我通常会做不同的事情，但为了简单起见，我这样做了。

代码很长，但您应该可以直接将其复制并粘贴到一个新的 PHP 文件中并在您的环境中运行它；无需设置。

具体问题

• 这是使用异常并在调用方处理它们的正确方法吗？
• 我什至应该为此使用例外吗？
• 我的骨架自定义异常是否正确？

代码

您可以在单独的窗口here 中查看副本。我会把它贴在这里。保存它并在您的环境中运行它，它应该可以按原样运行，无需任何修改：

注意：前面的代码很长

<?php

    error_reporting ( E_ALL | E_STRICT );




    class MemberLoginException extends Exception
    {

        public function __construct ( $message = null, $code = 0, Exception $previous = null )
        {
            parent::__construct ( $message, $code, $previous );
        }

    }




    class AccountsInsertException extends Exception
    {

        public function __construct ( $message = null, $code = 0, Exception $previous = null )
        {
            parent::__construct ( $message, $code, $previous );
        }

    }




    class AccountsManager
    {

        protected $_accounts = array ();
        protected $_lcUsernames = array ();     # all usernames in lowercase for checking if username is taken



        public function __construct ( array $accounts = null )
        {
            $this->setAllAccounts ( $accounts );
        }



        public function __destruct ()
        {
            unset ( $this->_accounts, $this->_lcUsernames );
        }



        public function __toString ()
        {
            $return = '';

            if ( count ( $this->_accounts ) > 0 ) :

                $return = '<table>';
                $return .= '<tr><th>Username</th><th>Password</th></tr>';

                foreach ( $this->_accounts as $account ) :

                    $return .= 
                    '<tr>
                        <td>'. htmlentities ( $account['username'], ENT_QUOTES, 'UTF-8' ) . '</td>
                        <td>'. htmlentities ( $account['password'], ENT_QUOTES, 'UTF-8' ) . '</td>
                    </tr>';

                endforeach;

                $return .= '</table>';

                return $return;
            endif;
        }



        public function Clear ()
        {
            $this->_accounts = array ();
            $this->_lcUsernames = array ();
        }



        public function Authenticate ( Member $member )
        {
            $username = strtolower ( $member->getUsername () );

            if ( count ( $this->_accounts ) ) :

                foreach ( $this->_accounts as $account ) :

                    if ( strtolower ( $account['username'] ) == $username )
                        return ( bool ) ( $account['password'] == $member->getPassword () );

                endforeach;

            else :
                return false;
            endif;
        }



        public function getAllAccounts ()
        {
            return $this->_accounts;
        }



        public function setAllAccounts ( array $newValue = null )
        {
            if ( is_null ( $newValue ) )
                $this->_accounts = array ();
            else
                $this->_accounts = $newValue;
                $this->_lcUsernames = array ();

                foreach ( $this->_accounts as $account )
                    $this->_lcUsernames[] = strtolower ( $account['username'] );

            return $this;
        }



        public function hasAccount ( $username )
        {
            return in_array ( strtolower ( $username ), $this->_lcUsernames, false );
        }



        public function AddAccount ( $username, $password )
        {

            /*
            Faster to be redundant by storing a lowercase copy of the username for comparison

            if ( array_key_exists ( strtolower ( $username ), array_change_key_case ( $this->_accounts ) ) )
                throw new AccountsInsertException ( 'Unable to create account; account already exists.' );
            */

            if ( $this->hasAccount ( $username ) )
                throw new AccountsInsertException ( 'Unable to create account; account already exists.' );

            $this->_accounts[] = array (
                'username' => $username,
                'password' => $password,
            );

            $this->_lcUsernames[] = strtolower ( $username );
            return $this;
        }



        public function RemoveAccount ( $username )
        {
            if ( $this->hasAccount ( $username ) ) :
                unset ( $this->_accounts[$username] );
                unset ( $this->_lcUsernames [ strtolower ( $username ) ] );
            endif;

            return $this;
        }



        public function __Debug ()
        {
            echo "\r<pre>\r";
            print_r ( $this->_accounts );
            echo "\r</pre>\r\r\r<pre>\r";
            print_r ( $this->_lcUsernames );
            echo "\r</pre>\r\r";
        }

    }




    class Member
    {

        protected $_username = '';
        protected $_password = '';



        public function __construct ( $username, $password )
        {
            $this->setUsername ( $username );
            $this->setPassword ( $password );
        }



        public function getUsername ()
        {
            return $this->_username;
        }



        public function setUsername ( $newValue )
        {
            $this->_username = ( string ) $newValue;
            return $this;
        }



        public function getPassword ()
        {
            return $this->_password;
        }



        public function setPassword ( $newValue )
        {
            $this->_password = ( string ) $newValue;
            return $this;
        }

    }


    # create a new accounts manager which stores all accounts and handles authentication
    # the Member class would be responsible for setting session variables, etc. Manager just checks user/pass.
    $manager = new AccountsManager ();

?><!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8" />

        <style>

            *
            {
                font-family: "Segoe UI", "Trebuchet MS", Tahoma, Arial, Helvetica, sans-serif;
            }

            body
            {
                margin: 4em 6em;
                line-height: 1.6em;
                font-size: smaller;
            }

            header
            {
                border-bottom: 2px solid #efefef;
                margin-bottom: 3em;
                padding-bottom: 1em;
            }

            h1, h2, h3, h4, h5, h6
            {
                font-weight: normal;
                letter-spacing: 1px;
                color: royalblue;
            }

            h5, h6
            {
                font-weight: bold;
            }

            header h1 sub, header h1 sup
            {
                font-size: small;
                color: #FF4400;
                letter-spacing: 2px;
            }

            section
            {
                border-bottom: 1px dotted #ccc;
                padding-bottom: 2em;
                margin-bottom: 3em;
            }

            table
            {
                border: 1px solid #eee;
                padding: 1em;
                border-right-width: 2px;
                border-bottom-width: 2px;
            }

            th
            {
                text-align: left;
                font-variant: small-caps;
                border-bottom: 1px dotted #ccc;
                padding-bottom: .75em;
                margin-bottom: .75em;
                letter-spacing: 1px;
                color: #FF4400;
            }

            td:hover
            {
                background-color: skyblue;
            }

            td
            {
                margin: 0;
                display: table-cell;
                padding: .5em;
            }

            pre
            {
                font-family: "Droid Sans Mono", Consolas, "Courier New", Courier, monospaced;
                border: 1px solid #E4E4E4;
                padding: 1em;
                line-height: 1em;
            }

            .error
            {
                color: red;
                border: 1px dotted #ccc;
            }

            .success
            {
                color: forestgreen;
                border: 1px dotted #e0e0e0;
            }

            .error, .success
            {
                padding: .75em;
                background-color: #FFFFCC;
                border: 1px solid #E4E4E4;
            }

        </style>

        <title>Sample Login System - Test Exceptions</title>
    </head>

    <body>

        <header>
            <h1>Simple Login System <sup>demonstrating exceptions&hellip;</sup></h1>
        </header>



        <section>
            <h2>No database required</h2>

            <p>To avoid time setting up your environment, this test simply uses a class that stores an array of accounts.
            Obviously, this isn't persistent (at this time) and it doesn't actually save anything anywhere except in the
            array during the script's lifetime. Upon the next request, the previous accounts will be erased.</p>
        </section>



        <section>
            <h2>Creating accounts...</h2>

            <?php

                $createList =
                    array (

                        array (
                            'username' => 'Daniel Elkins',
                            'password' => 'delkins[not-pass-for-anything]',
                        ),

                        array (
                            'username' => 'Jennifer Lynn',
                            'password' => 'lilJenn',
                        ),

                        array (
                            'username'=> 'Charlie Dog',
                            'password'=> 'grrrrr',
                        ),

                    );

                if ( $manager->setAllAccounts ( $createList ) instanceof AccountsManager ) : ?>

                    <p><strong>Accounts were created successfully!</strong> They should be listed in
                    a table below.</p>

                <?php

                else :

                ?>

                    <p class="error">There was an error creating your accounts...</p>

                <?php

                endif;

            ?>

        </section>


        <section>
            <h2>List of accounts</h2>

            <?php echo $manager; ?>

        </section>


        <section>
            <h2>Trying to create one that already exists...</h2>

            <?php

            try
            {
                $manager->AddAccount ( 'Daniel Elkins', 'delkins[not-pass-for-anything]'); ?>

                <p class="success">Account created successfully!</p>

                <?php

            }
            catch ( AccountsInsertException $exception )
            {
                ?>

                <p class="error"><?= $exception->getMessage (); ?></p>

                <?php

            }

            ?>

        </section>


        <section>
            <h2>Showing accounts again</h2>

            <?php echo $manager; ?>

        </section>


        <section>
            <h2>Valid login test</h2>

            <p>Logging in user `Daniel Elkins`&hellip;</p>

            <?php

            if ( $manager->Authenticate ( new Member ( 'Daniel Elkins', 'delkins[not-pass-for-anything]' ) ) ) : ?>

                <p class="success">Authentication successful!</p>

                <?php

            else :

            ?>

                <p class="error">Unable to login; invalid username or password!</p>

                <?php

            endif;

            ?>

        </section>


        <section>
            <h2><strong>Invalid</strong> login test</h2>

            <p>Logging in user `Doesnt_Exist`&hellip;</p>

            <?php

            if ( $manager->Authenticate ( new Member ( 'Doesnt_Exist', '1234' ) ) ) : ?>

                <p class="success">Authentication successful!</p>

                <?php

            else :

            ?>

                <p class="error">Unable to login; invalid username or password!</p>

                <?php

            endif;

            ?>

        </section>


        <section>
            <h2>Debug information</h2>

            <?php $manager->__Debug (); ?>

        </section>

    </body>

</html>

Answer 1

这是使用异常并在 调用方？

对我来说似乎是一种合理的方法。您正在抛出特定于类的异常，因此很容易捕获或传播它们，并且只抛出特定的异常，而不必捕获所有内容并进行过滤。

我什至应该为此使用例外吗？

如果您认为帐户存在的特殊情况，是的。

我的骨架自定义异常是否正确？

是的，尽管您可以考虑在其中添加元数据，例如在 AccountInsertException 中创建的帐户名称。这可能没有必要，但如果您发现自己处于有用的情况下，这只是需要考虑的事情。

否则代码在某些地方有点乱，但我假设部分原因是示例。